Information recording medium where address mark comprising pattern suitable for prevention of detection error is recorded, and cutting apparatus for reproducing the information recording medium

ABSTRACT

In an information recording medium including a plurality of sector fields and having various pieces of information recorded in the sector fields, the header field in each sector field includes a first field in which a continuously repeated pattern complying with the run length limitation in the predetermined range is recorded, a second field in which an address mark including a violation pattern different from a reproduced pattern obtained by reproducing the repeated pattern when a defective pit which cannot be recognized as a pit is included in pits representing the repeated pattern is recorded, the violation pattern exceeding the run length limitation in the predetermined range, and a third field in which address data is recorded.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to an information recording mediumsuch as a DVD (Digital Versatile Disk)-RAM (Random Access Memory) whichis used to record predetermined information. The present invention alsorelates to a cutting apparatus for recording header data on a master forthe information recording medium by exposure. Furthermore, the presentinvention relates to an information reproducing apparatus forreproducing the information recorded on the information recordingmedium. More specifically, the present invention relates to an addressmark indicating the recording position of address data included inheader data.

[0002] A plurality of sector fields are formed on an optical disk as theabove information recording medium. Each of these sector fields includesa header field and a recording field. Header data is recorded in theheader field in advance by embossing. User data is recorded in therecording field by using phase change.

[0003] A VFO (Voltage Frequency Oscillator) field, an AM (Address Mark)field, and a PID (Physical ID) field are sequentially arranged in theheader field. A continuously repeated pattern is recorded in the VFOfield. An address mark indicating the recording position of address datais recorded in the AM field by embossing. Various data including addressdata are recorded in the PID field by embossing.

[0004] Data are recorded on such an optical disk by using run lengthlimited code sequences having their run lengths limited in apredetermined range except for specific fields (e.g., AM fields). A runlength represents the number of consecutive, identical channel bits. Norun length code sequence includes a run of is (in channel bits). A runlength in this specification therefore represents a run of 0s (inchannel bits). For example, data to be recorded according to a runlength limitation corresponding to run lengths of 2 to 10 includes noconsecutive 1s. In addition, the run length of 0s between 1s is limitedto 2 to 10. Such a run length limitation corresponding to run lengths of2 to 10 is abbreviated as RLL (2, 10). Note that RLL is an abbreviationfor “Run Length Limited”.

[0005] Data to be recorded in each recording field of the optical diskis encoded into fixed-length block codes. A fixed-length block code is acode which is generated by encoding data at a constant ratio of codewords to data words, e.g., 2:1. In demodulating such a fixed-lengthblock code, if a block boundary is mistaken, proper modulation cannot beperformed. For this reason, an address mark is recorded in an AM fieldset before encoded data to allow detection of a proper block boundary inreproducing data, thereby demodulating the data. If a portion on whichdata is recorded is mistaken as an address mark, subsequent data cannotbe normally demodulated.

[0006] Note that in the edge recording scheme, NRZI (Non Return to ZeroInverted) processing is performed to invert the polarity of data at aposition corresponding to each channel bit “1”.

[0007] If pits representing a repeated pattern recorded in the above VFOfield includes a defective pit which cannot be recognized as a pit, thefollowing problem is posed. When the header field having a VFO fieldincluding a defective pit is reproduced, the reproduced pattern obtainedis affected by the defective pit. The reproduced pattern affected by thedefective pit then causes a detection error of an address mark. If anaddress mark is erroneously detected, the proper address data cannot beobtained. As a result, the optical disk cannot be normally played.

BRIEF SUMMARY OF THE INVENTION

[0008] It is an object of the present invention to provide the followinginformation recording medium, cutting apparatus, and informationreproducing apparatus.

[0009] (1) It is the first object of the present invention to provide aninformation recording medium on which an address mark which can benormally detected even if a defective pit is included in a VFO field isrecorded.

[0010] (2) It is the second object of the present invention to provide acutting apparatus which records, on a master for an informationrecording medium by exposure, an address mark which can be normallydetected even if a defective pit is included in a VFO field.

[0011] (3) It is the third object of the present invention to provide aninformation reproducing apparatus which reproduces address data inaccordance with an address mark which can be normally detected even if adefective pit is included in a VFO field.

[0012] In order to solve the above problem and achieve the aboveobjects, according to the present invention, an information recordingmedium, a cutting apparatus, and an information reproducing apparatushave the following arrangements.

[0013] (1) There is provided an information recording medium including aplurality of sector fields and having various pieces of informationrecorded in the sector fields, characterized in that the sector fieldcomprises a header field in which an address mark including a violationpattern exceeding a run length limitation in a predetermined range andaddress data complying with the run length limitation in thepredetermined range, a recording position of which is indicated by theaddress mark, are recorded, and a recording field on/from which data isrecorded/reproduced on the basis of the data recorded in the headerfield.

[0014] (2) There is provided a cutting apparatus for recording headerdata, by exposure, on a master for an information recording medium onwhich various pieces of information are recorded, characterized bycomprising recording means for recording an address mark including aviolation pattern exceeding a run length limitation in a predeterminedrange and address data complying with the run length limitation in thepredetermined range, a recording position of which is indicated by theaddress mark, by exposure.

[0015] (3) There is provided an information reproducing apparatus forreproducing information recorded on an information recording medium onwhich various pieces of information are recorded, characterized bycomprising address mark detection means for detecting an address markfrom a header field in which the address mark including a violationpattern exceeding a run length limitation in a predetermined range andaddress data complying with the run length limitation in thepredetermined range, a recording position of which is indicated by theaddress mark, are recorded, and reproducing means for reproducing theaddress data in accordance with the address mark detected by the addressmark detection means.

[0016] Additional objects and advantages of the invention will be setforth in the description which follows, and in part will be obvious fromthe description, or may be learned by practice of the invention. Theobjects and advantages of the invention may be realized and obtained bymeans of the instrumentalities and combinations particularly pointed outin the appended claims.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0017] The accompanying drawings, which are incorporated in andconstitute a part of the specification, illustrate presently preferredembodiments of the invention, and together with the general descriptiongiven above and the detailed description of the preferred embodimentsgiven below, serve to explain the principles of the invention.

[0018]FIG. 1 is a view for explaining the zones on an optical disk;

[0019]FIG. 2 is a view schematically showing the data structure on theoptical disk;

[0020]FIG. 3 is a view showing the rotational speed corresponding toeach zone on the optical disk and the number of sectors per track ineach zone;

[0021]FIG. 4 is a view showing the sector format of the optical disk;

[0022]FIG. 5 is a chart showing an example of an address mark;

[0023]FIG. 6A is a timing chart showing a state in which a normallyrecorded VFO area is reproduced with a normal binarization level;

[0024]FIG. 6B is a timing chart showing a state in which a VFO areaincluding a defective pit is reproduced with the normal binarizationlevel;

[0025]FIG. 6C is a timing chart showing a state in which a VFO areaincluding a defective pit is reproduced with a shifted binarizationlevel;

[0026]FIG. 7 is a timing chart showing the DSV values of the addressmark in FIG. 5;

[0027]FIG. 8 is a view for explaining the header fields defined betweengroove sectors or land sectors;

[0028]FIG. 9 is a view for explaining the header fields defined betweengroove sectors or land sectors;

[0029]FIG. 10 is a view for explaining the header fields defined betweengroove and land sectors;

[0030]FIG. 11 is a view for explaining the header fields defined betweengroove and land sectors;

[0031]FIG. 12 is a sectional view of an optical disk, schematicallyshowing the structure of the optical disk;

[0032]FIG. 13 is a block diagram showing the schematic arrangement of acutting apparatus;

[0033]FIG. 14 is a view for explaining a cutting modulation signal and awobble control signal generated by the formatting circuit of the cuttingapparatus;

[0034]FIG. 15 is a view for explaining cutting modulation signals forforming a single spiral structure;

[0035]FIG. 16 is a block diagram showing the schematic arrangement of anoptical disk apparatus as an information reproducing apparatus; and

[0036]FIG. 17 is a block diagram showing the schematic arrangement ofthe data reproducing circuit of the optical disk apparatus in FIG. 16.

DETAILED DESCRIPTION OF THE INVENTION

[0037] An embodiment of the present invention will be described belowwith reference to the accompanying drawing.

[0038] A DVD-RAM as an optical disk (information recording medium) willbe briefly described with reference to FIGS. 1 to 5. FIG. 1 is a viewfor explaining the zones on the optical disk. FIG. 2 shows the schematicdata structure on the optical disk. FIG. 3 shows the rotational speedscorresponding to the respective zones and the number of sectors pertrack in each zone. FIG. 4 schematically shows the sector format of theoptical disk. FIG. 5 shows an address mark.

[0039] An optical disk 1 is formed by coating the surface of a circularsubstrate made of a glass or plastic material or the like with a metalfilm made of tellurium, bismuth, or the like in the form of a doughnut.Concentric or spiral tracks (land tracks and groove tracks) are formedon the optical disk 1. These tracks include a plurality of sector fieldseach having a predetermined track length.

[0040] As shown in FIGS. 1 and 2, the data recording area of the opticaldisk 1 includes a lead-in area 2, a data area 3, and a lead-out area 4.Each area includes a plurality of zones. Each zone includes a pluralityof tracks.

[0041] An embossed data zone 5 and a rewritable data zone 6 are set inthe lead-in area 2. A reference signal and control data are recorded inthe embossed data zone 5 at the time of the manufacture of the opticaldisk. A guard track zone, a disk test zone, a drive test zone, a diskidentification data zone, a replacement management zone, and the likeare set in the rewritable data zone 6. A plurality of zones (zones 3a, .. . , 3x) are set in the data area 3. User data is recorded in this dataarea 3. The lead-out area 4 is a rewritable data zone. Data having thesame contents as those of the data recorded in the rewritable data zone6 is recorded in the lead-out area 4.

[0042] The numbers of sectors per track differ between the inner andouter peripheral sides of the optical disk 1. That is, the numbers ofsectors per track on the outer peripheral side are larger than those onthe inner peripheral side. For this reason, as shown in FIG. 3, thenumber of revolutions (rotational speed) of the optical disk 1 changesin units of zones. In other words, the rotational speed of the opticaldisk 1 decreases as the track to be subjected to reproduction/recordingshifts from the inner peripheral side to the outer peripheral side.

[0043] As shown in FIGS. 1 and 2, data are recorded on each track in thezones 3a, . . . , 3x of the data area 3 in units of ECC (ErrorCorrection Code) blocks.

[0044] The sector format will be described next with reference to FIG.4.

[0045] As shown in FIG. 4, one sector is constituted by about 267 bytes.Data modulated by 8-16 modulation is recorded on this sector. The 8-16modulation is a modulation scheme of modulating an 8-bit input codesequence into a 16-bit output code sequence. The input code sequence iscalled input bits, and the output code sequence is called channel bits.Note that one byte is equivalent to 16 channel bits.

[0046] The details of one sector will be described below. One sectorincludes 128-byte header field HF, 2-byte mirror field MF, and2,567-byte recording field RE.

[0047] Header data is recorded in header field HF by embossing in theprocess of manufacturing an optical disk. Header data is written fourtimes in header field HF to attain high header data detection precision.That is, header field HF includes header 1 field HF1, header 2 fieldHF2, header 3 field HF3, and header 4 field HF4 in which substantiallyidentical data are recorded. Each of header 1 field HFl and header 3field HF3 is constituted by 46 bytes. Each of header 2 field HF2 andheader 4 field HF4 is constituted by 18 bytes.

[0048] Header 1 field HF1 includes a 36-byte VFO (Voltage FrequencyOscillator)1 field, a 3-byte AM (Address Mark) field, a 4-byte PID(Physical ID)1 field, a 2-byte IED (ID Error Detection Code)1 field, anda 1-byte PA (Post Ambles)1 field.

[0049] Header 2 field HF2 includes an 8-byte VFO2 field, a 3-byte AMfield, a 4-byte PID2 field, a 2-byte IED2 field, and a 1-byte PA2 field.

[0050] Header 3 field HF3 includes a 36-byte VFO1 field, a 3-byte AMfield, a 4-byte PID3 field, a 2-byte IED3 field, and a 1-byte PAl field.

[0051] Header 4 field HF4 includes an 8-byte VFO2 field, a 3-byte AMfield, a 4-byte PID4 field, a 2-byte IED4 field, and a 1-byte PA2 field.

[0052] Sector information and a sector number are recorded as addressdata in each of the PIDI field, the PID2 field, the PID3 field, and thePID4 field.

[0053] A continuously repeated pattern (“000100010001 . . . ”) isrecorded in each of the VFO1 field and the VF02 field. This repeatedpattern is to ensure reliable reproduction of data from the optical diskeven when rotation of the optical disk varies. When the rotation of theoptical disk varies, the repeated pattern in the VFO field varies at thesame time. For this reason, a clock is generated to lock the PLL (PhaseLocked Loop) to this repeated pattern so as to read out data. With thisoperation, the data can be reliably reproduced.

[0054] An address mark is recorded in each AM field. The address markserves to detect the boundary between blocks. This address markindicates the recording position of the address data of a PIDn field.The address mark includes a violation pattern violating a predeterminedrun length limitation. For example, the address mark includes aviolation pattern (in channel bits) “100000000000001”which violates arun length limitation corresponding to run lengths of 2 to 10. In RLL(2, 10) codes, a pattern with a run length of 13 0s does not exist. Thatis, the inclusion of the pattern with a run length of 13 0s in theaddress mark prevents another pattern from being mistaken as an addressmark.

[0055] The address mark (in channel bits) in the present invention is“000100010000000000000100010001000000000000010001”, as shown in FIG. 5.The address mark in the present invention has a length of 48 channelbits. The following are the run lengths (runs of 0s) of this addressmark in the order arranged: 3, 3, 13, 3, 3, 13, 3. This means that inthe address mark a pattern “0001000100000000000001”including an oddnumber of (e.g., three) 1s repeats itself an even number of (e.g., two)times. With this pattern, the DC components are canceled out. Inaddition, “0001”, part of the repeated pattern recorded in the VFOfield, is recorded in the VFO field to be adjacent to the violationpattern “00000000000001”.

[0056] An error detection code for PID1 is recorded in the IED1 field.Similarly, error detection codes for PID2, PID3, and PID4 arerespectively recorded in the IED2 field, the IED3 field, and the IED4field.

[0057] State information necessary for demodulation is recorded in eachPA field. In addition, each PA field serves to adjust polarity such thatheader field HF ends with a space.

[0058] Mirror field MF is a field in which no data is recorded.

[0059] Recording field RF mainly serves as a field in which user data isrecorded. Recording field RF includes a (10+J/16)-byte gap field, a(20+K)-byte guard 1 field, a 35-byte VFO3 field, a 3-byte PS(Pre-Synchronous code) field, a 2,418-byte data field, a 1-byte PA3field, a (55−K)-byte guard 2 field, and a (25−J/16)-byte buffer field.Note that J is a random value from 0 to 15, and K is a random value from0 to 7. With these numbers, the start position of data write is randomlyshifted. As a result, degradation in recording film due to overwrite issuppressed.

[0060] The gap field is a field in which no data is recorded.

[0061] The guard 1 field is a field for preventing the VFO3 field frombeing affected by start portion degradation due to repeated overwrites,which is a marked characteristic of a phase change recording film. Theabove continuously repeated pattern is recorded in the VFO3 field. Async code is recorded in the PS field.

[0062] In the data field, a 4-byte data ID, a 2-byte data ID errorcorrection code IED (Data ID Error Detection Code), a sync code, an ECC(Error Correction Code), an EDC (Error Detection Code), 2,048-byte userdata, and the like are recorded. The data ID is data indicating sectorID1 to sector ID16. The data ID error correction code IED is an errorcorrection code for correcting a data ID error.

[0063] State information necessary for demodulation is recorded in thepost ambles PA3 field. This post ambles PA3 field also serves as a fieldindicating the end of the last byte of the preceding data field.

[0064] The guard 2 field is a field for preventing the data field frombeing affected by end portion degradation due to repeated recording,which is also a marked characteristic of a phase change recording film.

[0065] The buffer field is a field for absorbing variations in rotationof the optical disk 1 to prevent the data field from overlapping thesubsequent header field.

[0066] The PID fields (PID1 field, PID2 field, PID3 field, and PID4field) will be described in detail next. Each PID field is constitutedby a 1-byte (8-bit) sector information field and a 3-byte (24-bit)sector number field. A sector address is recorded in the sector numberfield.

[0067] The sector information is constituted by a 2-bit reserved field,a 2-bit PID number field, a 3-bit sector type field, and a 1-bit layernumber field.

[0068] No specific data is recorded in the reserved field.

[0069] A PID number is recorded in the PID number field. For example,“00”representing PID1 is recorded in the PID number field in header 1field HF1; “01” representing PID2, in the PID number field in header 2field HF2; “10” representing PID3, in the PID number field in header 3field HF3; and “11” representing PID4, in the PID number field in header4 field HF4.

[0070] Land and groove tracks are identified from the sector numbersrecorded in the sector number fields in header 1 field HF1 to header 4field HF4.

[0071] The following data are recorded in the sector type field:“000”representing a read only sector (Read only sector); “001”, “010”,or “011”representing a reserved sector (Reserved); “100”representing thefirst rewritable sector of a land or groove track (Rewritable firstsector); “101”representing the last rewritable sector of a land orgroove track (Rewritable last sector); “110”representing a sector beforethe last rewritable sector of a land or groove track (Rewritable beforelast sector); and “111”representing another rewritable sector of a landor groove track (Rewritable other sector).

[0072] In the layer number field, a “1”or “0” representing layer 1 orlayer 0 is recorded.

[0073] An example of detection error of the repeated pattern recorded ina VFO field will be described next with reference to FIGS. 6A to 6C. Apattern “0001”in channel bits is repeatedly recorded in the VFO field.When the period of such a repeated pattern is represented by a channelclock period T, the period becomes 4T. For this reason, this pattern isalso called a 4T pattern. Record pits are formed such that a positioncorresponding to a channel bit “1”coincides with the start or end pointof each record pit. Referring to FIGS. 6A to 6C, the elliptical marksrepresent the record pits.

[0074]FIG. 6A shows a state in which the normally recorded VFO patternis normally detected. In this case, the solid curve represents thewaveform of the reproduced signal obtained from the pit string. Thisreproduced signal is converted into a binary signal with thebinarization level indicated by the dashed line. For example, thebinarization level is determined by calculating a DSV (Digital SumValue) from the duty of the binary signal, and performing feedbackcontrol using the calculated value as a deviation. Each edge of thebinary signal corresponds to a “1”of the reproduced bit string.

[0075]FIG. 6B shows a state in which an abnormally recorded VFO patternis detected. For example, the abnormally recorded VFO pattern is a VFOpattern including a record pit with insufficient depth/height. Referringto FIG. 6B, the record pit with insufficient depth/height is indicatedby hatching. Such a record pit with insufficient depth/height is formedwhen, for example, a lack of filling resin locally occurs in a masteringprocess, a pit defect is present in a disk substrate owing to somecause, or dust adheres to the disk. Subsequently, the pits indicated byhatching will be referred to as defective pits.

[0076] A defective pit has a depth (when the pit is a concave) smallerthan λ/4 at which the maximum reflectance change can be theoreticallyobtained. For this reason, the level of the reproduced signal does notsufficiently decrease at the defective pit position. In this case, λrepresents the laser wavelength, which is, for example, set to 650 nm.In this case, the defective pit is not recognized as a pit. As a result,a 12T pattern, which does not exist among RLL (2, 10) codes, isdetected, as shown in FIG. 6B.

[0077] The address mark recorded in the AM field includes a violationpattern “100000000000001”which violates a run length limitation in apredetermined range. More specifically, even a violation patternviolating the run length limitation includes a violation patternexceeding the upper limit value of the run length limitation.

[0078] When an area including a defective pit is reproduced, anerroneously reproduced signal is inevitably obtained. The address markrecorded on the AM field serves to detect a block boundary. This addressmark is set immediately after the VFO field. That is, a repeated VFOpattern is always recorded before each address mark. When record pitsrepresenting this repeated VFO pattern include a defective pit, aviolation pattern which is discordant with the run length limited codesin the predetermined range is generated. A defective pit in a repeatedVFO pattern greatly differs from a defective pit included in arbitrarydata in this respect.

[0079] The present invention exploits this aspect to prevent a detectionerror of an address mark. More specifically, when a defective pit whichis not recognized as a pit is included in a VFO field, a violationpattern different from a reproduced pattern affected by this defectivepit is included in an address mark. This prevents any pattern from beingmistaken as an address mark owing to a reproduced pattern affected by adefective pit. FIG. 5 shows an example of an address mark.

[0080] The violation pattern included in the address mark shown in FIG.5 never appears in a reproduced pattern affected by a defective pit likethe one shown in FIG. 6B. Obviously, this violation pattern neverappears in a reproduced pattern affected by more than one defective pit.

[0081]FIG. 6C shows a state in which an abnormally recorded VFO patternis erroneously detected. The abnormally recorded VFO pattern is apattern including a defective pit like the one described above. In thiscase, the state in which the pattern is erroneously detected indicates astate in which the pattern is detected with a binary level whichdeviates from the proper level for some reason. The binary leveldeviates from the amplitude center of the reproduced signal in the VFOfield in the presence of a large defect.

[0082] In the state shown in FIG. 6C, the binary level deviates to thelower side with respect to the reproduced signal. In this case, aviolation pattern with a run length of 13 is detected. That is, apattern identical to the violation pattern included in the address markshown in FIG. 5 is detected.

[0083] In the address mark in FIG. 5, however, part of the repeated VFOpattern recorded in the VFO field is present adjacent to the violationpattern exceeding the run length limitation. For this reason, thisaddress mark always becomes a pattern different from the reproducedpattern shown in FIG. 6C.

[0084] As the address mark shown in FIG. 5 is used, it can be accuratelydetected even if the pattern shown in FIG. 6B or 6C is reproduced.

[0085] The DSV of the address mark in FIG. 5 will be described next withreference to FIG. 7. FIG. 7 shows changes in DSV of an address markformed by repeating an odd pattern, including an odd number of 1s,twice. The polarity of an odd pattern is inverted at the start and endpoints when NRZI conversion occurs. Referring to FIG. 7, the “oddpattern” is a pattern of 4T—14T—4T, which includes three 1s.

[0086] Referring to FIG. 7, high level (H) and low level (L) of thebinary waveform respectively correspond to a space and a pit. Thelengths of pits and spaces are expressed by channel bit periods T abovethe binary waveform. The address mark in FIG. 7 is expressed in channelbits as “000100010000000000000100010001000000000000010001”. The lowerportion of FIG. 7 shows changes in DSV value in units of channel bits ofthe address mark. Since this address mark is formed by repeating the oddpattern twice, the changes in DVS value exhibit symmetry, and the DSVvalue ends with a value near 0. When an odd pattern is repeated an evennumber of times, such a result is obtained by a net effect. If a patternformed by repeating an odd pattern an even number of times is used as anaddress mark to suppress DC components, a binarization circuit can beimplemented by a simple arrangement.

[0087] Address mark patterns in the present invention will be describedin more detail below. The pattern shown in FIG. 5 is only an example ofa special pattern in the present invention. A special pattern in thisembodiment can be expressed as follows.

[0088] If a repeated VFO pattern in a VFO field satisfies a run lengthm, this address mark in the present invention includes a violationpattern satisfying a run length n (n>m, n≠rm+(r−1), r: natural number).This means that the address mark in the present invention includes aviolation pattern “100000000000001”. Note that the address mark shown inFIG. 5 satisfies m=3, n=13, and r=3.

[0089] This address mark in the present invention includes a specialpattern in which a pattern satisfying the run length m is presentadjacent to a violation pattern satisfying the run length n. That is,the address mark in the present invention includes a special pattern“10001000000000000010001”.

[0090] In addition, this address mark in the present invention includesa pattern in which a special pattern including an odd number of 1srepeats itself an even number of times. That is, the address mark inthis present invention includes a pattern“00010000000000000100010001000000000000010001”in which a special pattern“0001000000000000010001” repeats itself an even number of times. Inother words, the address mark in the present invention includes apattern in which a special 22-channel-bit pattern having a channel bit“1”appearing at the 4th, 8th, and 22nd channel bits repeats itself aneven number of times. That is, the address mark in the present inventionincludes a pattern “00010000000000000100010001000000000000010001”inwhich a special pattern “000100000000000010001”repeats itself an evennumber of times.

[0091] The header fields defined between groove sectors, between landsectors, and between groove and land sectors will be described next withreference to FIGS. 8 to 11. FIGS. 8 and 9 are views for explainingheader fields HF between groove sectors or land sectors. FIGS. 10 and 11are views for explaining header fields HF between groove and landsectors.

[0092]FIGS. 8 and 9 show how land sector L01, groove sector G11, landsector L21, groove sector G31, land sector L41, and groove sector G51are formed on the optical disk from the outer to the inner peripheralside. The distance between the centers of adjacent tracks will bereferred to as a track pitch. For example, the distance from the centerof the track on which land sector L22 is formed to the center of thetrack on which groove sector G32 is formed is the track pitch. Referringto FIG. 9, reference symbol N denotes the number of sectors per track(round). The value of N assumes an integer from 17 to 40.

[0093]FIGS. 10 and 11 show how groove sector G1n, land sector L2n,groove sector G3n, land sector L4n, and a groove sector G5n are formedon the optical disk from the outer to the inner peripheral side. Thedistance between the centers of adjacent tracks will be referred to as atrack pitch. For example, the distance from the center of the track onwhich land sector L40 is formed to the center of the track on whichgroove sector G50 is formed is the track pitch. Referring to FIG. 11,reference symbol N denotes the number of sectors per track (round). Thevalue of N assumes an integer from 17 to 40.

[0094] Header fields HF defined between groove sectors or land sectorswill be described first with reference to FIGS. 8 and 9.

[0095] As shown in FIG. 8, a plurality of pits P are formed in eachheader field HF. The centers of the pits constituting header 1 fieldH12-1 and header 2 field H12-2 are located on the extended line of theboundary between land sector L02 and groove sector G12 (or between landsector L01 and groove sector G11). The centers of the pits constitutingheader 3 field H22-3 and header 4 field H22-4 are located on theextended line of the boundary between groove sector G12 and land sectorL22 (or between groove sector Gll and land sector L21). The centers ofthe pits constituting header 1 field H32-1 and header 2 field H32-2 arelocated on the extended line of the boundary between land sector L22 andgroove sector G32 (or between land sector L21 and groove sector G31).The centers of the pits constituting header 3 field H42-1 and header 4field H42-4 are located on the extended line of the boundary betweengroove sector G32 and land sector L42 (or between groove sector G31 andland sector L41). The centers of the pits constituting header 1 fieldH52-1 and header 2 field H52-2 are located on the extended line of theboundary between land sector L42 and groove sector G52 (or between landsector L41 and groove sector G51). The centers of the pits constitutingheader 3 field H62-3 and header 4 field H62-4 are located on theextended line of the boundary between groove sector G52 and land sectorL62 (or between groove sector G51 and land sector L61).

[0096]FIG. 9 shows the relationship between the sector numbers of theheaders of header fields HF defined between groove sectors. Thisrelationship will be described below with reference to, for example, thesector numbers of header field HF between groove sector G11 and groovesector G12. Header 1 field H12-1, header 2 field H12-2, header 3 fieldH22-3, and header 4 field H22-4 are formed between groove sector G11 andgroove sector G12. The sector number of header 1 field H12-1 isrepresented by (n+3N). The sector number of header 2 field H12-2 isrepresented by (n+3N). The sector number of header 3 field H22-3 isrepresented by (n+2N). The sector number of header 4 field H22-4 isrepresented by (n+2N). In other words, the relationship between thesector numbers of the respective headers formed between the groovesectors can be expressed as (sector number of header 1 field or header 2field)>(sector number of header 3 field or header 4 field).

[0097]FIG. 9 shows the relationship between the sector numbers of theheaders of header fields HF arranged between land sectors. Thisrelationship will be described below with reference to, for example, thesector numbers of the respective headers arranged between land sectorL21 and land sector L22. Header 1 field H32-1, header 2 field H32-2,header 3 field H22-3, and header 4 field H22-4 are formed between landsector L21 and land sector L22. The sector number of header 1 fieldH32-1 is represented by (n +N). The sector number of header 2 fieldH32-2 is represented by (n+N). The sector number of header 3 field H22-3is represented by (n +2N). The sector number of header 4 field H22-4 isrepresented by (n+2N). More accurately, the relationship between thesector numbers of the respective heads arranged between the land sectorscan be expressed as (sector number of header 1 field or header 2field)<(sector number of header 3 field or header 4 field).

[0098] If, therefore, it is determined upon reproduction of headers that“(sector number of header 1 field or header 2 field)>(sector number ofheader 3 field or header 4 field) holds, the sector (track) after theseheaders is identified as a groove sector (groove track), andreproduction processing corresponding to the groove sector can beperformed. In contrast to this, if, therefore, it is determined uponreproduction of headers that “(sector number of header 1 field or header2 field)<(sector number of header 3 field or header 4 field) holds, thesector (track) after these headers is identified as a land sector (landtrack), and reproduction processing corresponding to the land sector canbe performed.

[0099] Header fields HF defined between groove and land sectors, i.e.,header fields HF formed on the transitional portions between groove andland sectors, will be described next with reference to FIGS. 10 and 11.

[0100] As shown in FIG. 10, a plurality of pits P are formed in headerfields HF. The centers of the pits constituting header 3 field H20-3 andheader 4 field H20-4 are located on the extended line of the boundarybetween groove sector G10 and land sector L20. The centers of the pitsconstituting header 1 field H30-1 and header 2 field H30-2 are locatedon the extended line of the boundary between land sector L20 and groovesector G30 (or between groove sector G1n and land sector L2n). Thecenters of the pits constituting header 3 field H40-3 and header 4 fieldH40-4 are located on the extended line of the boundary between groovesector G30 and land sector L40 (or between land sector L2n and groovesector G3n). The centers of the pits constituting header 1 field H50-1and header 2 field H50-2 are located on the extended line of theboundary between land sector L40 and groove sector G50 (or betweengroove sector G3n and land sector L4n). The centers of the pitsconstituting header 3 field H60-3 and header 4 field H60-4 are locatedon the extended line of the boundary between groove sector G50 and landsector L60 (or between land sector L4n and groove sector G5n). Thecenters of the pits constituting header 1 field H70-1 and header 2 fieldH70-2 are located on the extended line of the boundary between landsector L60 and groove sector G70.

[0101]FIG. 11 shows the relationship between the sector numbers of theheads of header fields HF defined between the land and groove sectors(transition from a land sector to a groove sector). This relationshipwill be described below with reference to, for example, the sectornumbers of the respective headers arranged between land sector L2n andgroove sector G30. Header 1 field H30-1, header 2 field H30-2, header 3field H40-3, and header 4 field H40-4 are formed between land sector L2nand groove sector G30. The sector number of header 1 field H30-1 isrepresented by (m+3N). The sector number of header 2 field H30-2 isrepresented by (m+3N). The sector number of header 3 field H40-3 isrepresented by (m+2N). The sector number of header 4 field H40-4 isrepresented by (m+2N). This means that the relationship between thesector numbers of the respective headers between the land and groovesectors can be expressed as (sector number of header 1 field or header 2field)>(sector number of header 3 field or header 4 field).

[0102]FIG. 11 shows the relationship between the sector numbers of theheaders of header fields HF defined between groove and land sectors(transition from a groove sector to a land sector). This relationshipwill be described below with reference to, for example, the sectornumbers of the respective headers arranged between groove sector G3n andland sector L40. Header 1 field H50-1, header 2 field H50-2, header 3field H40-3, and header 4 field H40-4 are formed between groove sectorG3n and land sector L40. The sector number of header 1 field H50-1 isrepresented by (m+N). The sector number of header 2 field H50-2 isrepresented by (m+N). The sector number of header 3 field H40-3 isrepresented by (m+2N). The sector number of header 4 field H40-4 isrepresented by (m+2N). In other words, the relationship between thesector numbers of the respective headers arranged between the groove andland sectors can be expressed as (sector number of header 1 field orheader 2 field)<(sector number of header 3 field or header 4 field).

[0103] If, therefore, it is determined upon reproduction of headers that“(sector number of header 1 field or header 2 field)>(sector number ofheader 3 field or header 4 field) holds, the sector (track) after theseheaders is identified as a groove sector (groove track), andreproduction processing corresponding to the groove sector can beperformed. In contrast to this, if it is determined upon reproduction ofheaders that “(sector number of header 1 field or header 2field)<(sector number of header 3 field or header 4 field) holds, thesector (track) after these headers is identified as a land sector (landtrack), and reproduction processing corresponding to the land sector isperformed.

[0104] As described above with reference to FIGS. 8 to 11, a sector(track) after given headers can be identified as a land sector (landtrack) or a groove sector (groove track) on the basis of therelationship in magnitude between the header 1 field (or header 2 field)and the header 3 field (or header 4 field) obtained upon reproduction ofthe headers.

[0105] The positional relationship between groove and land sectors(groove and land tracks) and header fields HF will be described below.

[0106] A scheme of switching the positions of groove and land tracks inunits of revolutions is called a single spiral scheme. In an opticaldisk using such a single spiral scheme, if header fields are recordedbetween land and groove tracks as described above, cutting can berealized by one beam. The sector located between groove and land trackswill be referred to as a fast sector. FIGS. 10 and 11 show the headerfields of the fast sectors. Referring to FIGS. 8 to 11, the polaritiesof the spiral tracks are switched as the tracks are switched betweenland and groove tracks.

[0107] In the single spiral scheme in which the positions of groove andland tracks are switched in this manner in units of revolutions, thepolarities of groove and land tracks must be switched in tracking. Forthis reason, the arrangement of headers in a sector at transition from agroove track to a land track or from a land track to a groove trackdiffers from that of headers in other sectors.

[0108] A method of manufacturing an optical disk will be described next.First of all, a glass disk is manufactured. This glass disk is coatedwith a photoresist (photosensitive resin) to form a photoresist disk.This photoresist disk is rotated, and a laser beam is irradiated on therotated photoresist disk. Tracks and header data are recorded on thephotoresist disk by exposure. When the photoresist disk on which thetracks and the headers are recorded by exposure is developed, thephotoresist portions corresponding to the exposed portions dissolve in adeveloping solution. As a result, tracks and header data are formed onthe photoresist disk.

[0109] This process of forming the tracks and the header data on thephotoresist disk is called a cutting process. This cutting processing isimplemented by a cutting apparatus. For example, this cutting apparatusincludes an optical head for irradiating a laser beam on a photoresistdisk. A metal is deposited on the photoresist disk on which the tracksand the headers are formed to manufacture a master. This master isplated with Ni, and the Ni-plated layer is peeled off from this master.The peeled Ni-plated layer becomes a mold called a stamper for anoptical disk. An optical disk is manufactured by using this stamper as amold.

[0110] In the above cutting process, the optical head of the cuttingapparatus is moved by the track pitch toward the outer peripheral sideat a uniform velocity per revolution of the disk. The portions which areirradiated with a laser beam become grooves, and the portions which arenot irradiated with the laser beam become lands.

[0111]FIG. 11 shows the fast sectors of three tracks with sector numbersm, (m+N), and (m+2N). In a cutting process, after land sector L4n isformed, a laser beam is shifted from the center of the trackcorresponding to land sector L4n to the outer peripheral side by halfthe track pitch to record header 1 field H50-1 and header 2 field H50-2.The laser beam is further shifted from the center of the trackcorresponding to land sector L4n to the inner peripheral side by halfthe track pitch to record header 1 field H50-3 and header 2 field H50-4.

[0112] A mirror portion is formed by not irradiating a laser beam. Agroove portion is formed by irradiating a laser beam. In this case, wavygrooves are formed by oscillating the spot of a laser beam sinusoidallyat a channel bit period of 186 from the inner to the outer peripheralside. This signal component is used as a reference signal for thegeneration of a clock for a data write. In the process of one revolutionfrom sector number m to sector number (m+N−1), recording is performedaccording to the above procedure. In the process of one revolution fromsector number (m+N) to sector number (m+2N−1), no laser beam isirradiated. This operation is repeated to form header fields like thoseshown in FIG. 11.

[0113]FIGS. 8 and 9 show the header structure of a sector other than afast sector. With the cutting process described above, a pair of header1 field and header 2 field as the first-half headers of a groove sector,and a pair of header 3 field and header 4 field as the second-halfheaders of the groove sector are recorded. Note that the first-halfheaders of a land sector are recorded one revolution before thesecond-half headers are recorded.

[0114] The structure of an optical disk will be described next withreference to FIG. 12.

[0115] An optical disk substrate 200 is made of a transparent materialsuch as a plastic material and is replicated from a mold called astamper. Header fields HF and recording fields RF are recorded on thesubstrate 200. Header data is recorded in each header field HF byforming embossed pits P. Groove tracks GT and land tracks LT are formedin recording fields RF.

[0116] Each embossed pit P has a convex shape, each groove track GT hasa convex shape, and each land track LT has a concave shape when viewedfrom the incident side of a reproduction laser beam. A protective film201, a recording film 202, a protective film 203, and a reflecting film204 are sequentially stacked on the uneven recording surface of thesubstrate 200 in the order named. Each chain line in FIG. 12 indicatesthe center of groove track GT or land track LT. Embossed pits Pconstituting a header fields are located on a line shifted from thecenter lines of groove track GT and land track LT by Wt/2. In this case,Wt represents a track pitch, which is the distance between the centersof groove track GT and land track LT.

[0117] Embossed pits P are formed in a staggered pattern by causing alaser spot to wobble by Wt/2 in a cutting process for groove track GT.

[0118] As shown in FIGS. 9 and 11, the formation of embossed pits P in astaggered pattern in header field HF obviates the need for making thewidth of groove track GT different from the diameter of embossed pit P.That is, groove tracks GT and embossed pits P can be cut by the samebeam. The cutting apparatus can therefore be greatly simplified.

[0119] The cutting apparatus will be described next with reference toFIGS. 13 to 15. Header data including a repeated VFO pattern, theaddress mark and address data shown in FIG. 5, and the like is recordedat a predetermined position by exposure using this cutting apparatus.FIG. 13 shows the schematic arrangement of the cutting apparatus. FIG.14 is a view for explaining a cutting modulation signal and a wobblecontrol signal generated by the formatting circuit of the cuttingapparatus. FIG. 15 is a view for explaining cutting modulation signalsfor forming a single spiral structure.

[0120] The schematic arrangement of the cutting apparatus will bedescribed first with reference to FIG. 13. A laser beam (Ar or Kr laserbeam) emitted by a laser source 41 is incident on a laser beam opticalaxis control system 42 for adjusting the optical axis. The laser beamoptical axis control system 42 adjusts the optical axis of the laserbeam. The laser beam adjusted by the laser beam optical axis controlsystem 42 is reflected by a mirror 43 to enter a beam modulation system44 controlled by a formatting circuit 49.

[0121] The beam modulation system 44 is constituted by anacousto-optical modulator (AOM) 44a and an acousto-optical deflector(AOD) 44 b. The acousto-optical modulator 44 a modulates the laser beamin accordance with a cutting modulation signal supplied from theformatting circuit 49. The acousto-optical deflector 44 b deflects thelaser beam in accordance with an instruction supplied from theformatting circuit 49. More specifically, the header data including therepeated VFO pattern, the address mark and address data shown in FIG. 5,and the like is reflected in the laser beam by the beam modulationsystem 44. As a result, the header data including the repeated VFOpattern, the address mark and address data shown in FIG. 5, and the likeis recorded on the master by exposure. The formatting circuit 49includes a ROM 50 and serves to generate a cutting signal fordetermining the laser output and exposure position and a wobble controlsignal indicating the wobble amount and wobble direction. The ROM 50will be described in detail later.

[0122] The incoming laser beam on the beam modulation system 44 ismodulated by the acousto-optical modulator 44 a and deflected by theacousto-optical deflector 44 b. The laser beam modulated by the beammodulation system 44 reaches a beam shaping system 45 constituted by pinholes and slits. The diameter and shape of the laser beam are adjustedby the beam shaping system 45. The laser beam adjusted by the beamshaping system 45 is sent onto a beam monitor system 46. The beammonitor system 46 monitors the shape of the laser beam.

[0123] The laser beam monitored by the beam monitor system 46 is guidedto a mirror 47 and focused and irradiated onto a photoresist disk 40through an objective lens 48. The photoresist disk 40 is obtained bycoating a glass disk with a photoresist. The portions, of thephotoresist disk 40, on which the laser beam is irradiated becomeconcave portions upon etching.

[0124] In a cutting process, the photoresist disk 40 is rotated at auniform velocity by a spindle motor 39. The photoresist disk 40 is alsomoved in a predetermined direction, together with the spindle motor 39,by a feed screw 51. With this movement, the laser irradiated through theobjective lens 48 is moved from the inner to the outer peripheral sideof the photoresist disk 40. The feed screw 51 moves the photoresist disk40 together with the spindle motor 39 under the control of a feedcontroller 52. The laser beam is moved from the inner to the outerperipheral side by the track pitch per revolution of the photoresistdisk 40 under the control of the feed controller 52. A portion which isirradiated with the laser beam moved in this manner becomes a groovetrack, and a portion which is not irradiated with the laser beam becomesa land track. By flickering the laser beam, header data constitutingheader field HF is recorded.

[0125] A ROM 50 in the formatting circuit 49 will be described below. Aconversion table for implementing 8-16 modulation is stored in the ROM50. This conversion table is used to modulate an 8-bit input codesequence (to be referred to as source data hereinafter) into a 16-bitoutput code sequence (to be referred to a converted code hereinafter). Acutting modulation signal is generated on the basis of a converted codeobtained by this conversion table.

[0126] The cutting modulation signal and wobble control signal generatedby the formatting circuit 49 will be described next with reference toFIG. 14.

[0127] The cutting modulation signal is a signal used as a modulationsignal for the laser source 41 of the cutting apparatus. Assume that inFIG. 14, the level of the cutting modulation signal is proportional tothe output of a laser beam.

[0128] The wobble control signal is a signal for controlling thedeflection angle in the acousto-optical deflector 44 b to shift theposition of a beam. When the level of the wobble control signal ishigher than zero level, the irradiation position of the beam movesupward from the center position of a track. When the level of the wobblecontrol signal is smaller than zero level, the irradiation position ofthe beam moves downward from the center position of a track.

[0129] As shown in FIG. 14, portions where the level of the wobblecontrol signal is higher than zero level, i.e., header 1 field andheader 2 field portions, are shifted upward from the center position ofa track, whereas portions where the level of the wobble signal is lowerthan zero level, i.e., header 3 field and header 4 field portions, areshifted downward from the center position of the track. A portion wherethe level of the wobble control signal coincides with zero level, i.e.,a groove portion, is formed at the center position of the track.

[0130] When the cutting modulation signal is set at high level, aconcave portion is formed on the master. Hence, when the cuttingmodulation signal is set at high level, an embossed pit is formed.

[0131] Cutting modulation signals for forming a single spiral structurewill be described next with reference to FIG. 15.

[0132] Each of cutting modulation signals a to d is a signalcorresponding to one track.

[0133] When the cutting modulation signal a is set at low level, landtrack LT forming a track a is formed. When the cutting modulation signala is set at high level, groove track GT forming the track a is formed.

[0134] When the cutting modulation signal b is set at low level, landtrack LT forming a track b is formed. When the cutting modulation signalb is set at high level, groove track GT forming the track b is formed.

[0135] When the cutting modulation signal c is set at low level, landtrack LT forming a track c is formed. When the cutting modulation signalc is set at high level, groove track GT forming the track c is formed.

[0136] When the cutting modulation signal d is set at low level, landtrack LT forming a track d is formed. When the cutting modulation signald is set at high level, groove track GT forming the track d is formed.

[0137] Every time the photoresist disk makes one revolution, the cuttingmodulation signals are switched between the cutting modulation signalsa, b, c, and d. With this operation, a single spiral structure isrealized.

[0138] An optical disk apparatus as an information reproducing apparatuswill be described next with reference to FIGS. 16 and 17. The opticaldisk apparatus to be described below is designed to record/reproducedata on/from an optical disk on which header data including the addressmark shown in FIG. 5 is recorded. FIG. 16 shows the schematicarrangement of the optical disk apparatus. FIG. 17 shows the schematicarrangement of the data reproducing circuit of the optical diskapparatus.

[0139] The schematic arrangement of the optical disk apparatus will bedescribed first with reference to FIG. 16.

[0140] In this optical disk apparatus, a convergent light beam isirradiated on an optical disk 1, and the light beam reflected by theoptical disk 1 is received, thereby reproducing data recorded on theoptical disk 1 and reflected in the received reflected light beam. Inaddition, the optical disk apparatus irradiates a light beam on theoptical disk 1 to record data on the optical disk 1.

[0141] The optical disk 1 is rotated by a motor 3 at different numbersof revolutions in units of zones of the optical disk. This motor 3 iscontrolled by a motor control circuit 4. Data is recorded/reproducedon/from the optical disk 1 by an optical head 5. The optical head 5 isfixed to a driving coil 7 as a constituent of the movable portion of alinear motor 6. The driving coil 7 is connected to a linear motorcontrol circuit 8.

[0142] A speed detector 9 is connected to the linear motor controlcircuit 8. A speed signal indicating the speed of the optical head 5 anddetected by the speed detector 9 is sent to the linear motor controlcircuit 8. A permanent magnet (not shown) is mounted on the fixedportion of the linear motor 6. When the driving coil 7 is energized bythe linear motor control circuit 8, the optical head 5 is radially movedalong the optical disk 1.

[0143] The optical head 5 has an objective lens 10 supported on a wireor leaf spring (not shown). The objective lens 10 can be moved in thefocusing direction (along the optical axis of the lens) by a drivingcoil 11. The objective lens 10 can also be moved in the trackingdirection (a direction perpendicular to the optical axis of the lens) bya driving coil 12.

[0144] A laser beam is emitted by a semiconductor laser oscillator 19under the control of a laser control circuit 13. The laser controlcircuit 13 is constituted by a modulation circuit 14 and a laser drivingcircuit 15 and operates in synchronism with a recording clock signalsupplied from a PLL circuit 18. The modulation circuit 14 modulatesrecord data supplied from an error correction circuit 32 into a signalsuitable for recording, i.e., 8-16 modulated data. The laser drivingcircuit 15 drives the semiconductor laser oscillator (or argon/neonlaser oscillator 19) in accordance with the 8-16 modulated data from themodulation circuit 14.

[0145] The PLL circuit 18 generates a recording clock byfrequency-dividing a fundamental block signal generated by a quartzoscillator 17. The fundamental clock signal is frequency-divided by afrequency division value set by a CPU 30. Alternatively, the fundamentalclock signal is frequency-divided into a frequency corresponding to thetime intervals at which header fields HF are reproduced. In thereproduction mode, the PLL circuit 18 generates a reproduction clocksignal corresponding to a reproduced sync code. In addition, the PLLcircuit 18 selectively outputs a recording or reproduction clock signalin accordance with a control signal from the CPU 30 and a signal from abinarization circuit 61 of a data reproducing circuit 16.

[0146] A laser beam emitted by the semiconductor laser oscillator 19 isirradiated on the optical disk 1 through a collimator lens 20, a halfprism 21, and the objective lens 10. The light reflected by the opticaldisk 1 is guided to a photodetector 24 through the objective lens 10,the half prism 21, a focusing lens 22, and a cylindrical lens 23.

[0147] The photodetector 24 is made up of four photodetection cells 24a, 24 b, 24 c, and 24 d. An output signal from the photodetection cell24 a is supplied to one terminal of an adder 26 a through an amplifier25 a. An output signal from the photodetection cell 24 b is supplied toone terminal of an adder 26 b through an amplifier 25 b. An outputsignal from the photodetection cell 24 c is supplied to the otherterminal of the adder 26 a through an amplifier 25 c. An output signalfrom the photodetection cell 24 d is supplied to the other terminal ofan adder 26 d through an amplifier 25 d.

[0148] The output signal from the photodetection cell 24 a is suppliedto one terminal of the adder 26 c through the amplifier 25 a. The outputsignal from the photodetection cell 24 b is supplied to one terminal ofthe adder 26 c through the amplifier 25 b. The output signal from thephotodetection cell 24 c is supplied to the other terminal of the adder26 d through the amplifier 25 c. The output signal from thephotodetection cell 24 d is supplied to the other terminal of the adder26 b through the amplifier 25 d.

[0149] An output signal from the adder 26 a is supplied to the invertinginput terminal of a differential amplifier OP2, and an output signalfrom the adder 26 b is supplied to the non-inverting input terminal ofthe differential amplifier OP2. The differential amplifier OP2 outputs asignal concerning the focus point and corresponding to the differencebetween the output signals from the adders 26 a and 26 b. This output issupplied to a focusing control circuit 27. An output signal from thefocusing control circuit 27 is supplied to the driving coil 12. Withthis operation, a laser beam is always controlled in a just focusedstate on the optical disk 1.

[0150] An output signal from the adder 26 c is supplied to the invertinginput terminal of a differential amplifier OP1, and an output signalfrom the adder 26 d is supplied to the non-inverting input terminal ofthe differential amplifier OP1. The differential amplifier OP1 outputs atrack difference signal corresponding to the difference between the twooutput signals from the adders 26 c and 26 d. This output is supplied toa tracking control circuit 28. The tracking control circuit 28 generatesa track driving signal in accordance with the track difference signalfrom the differential amplifier OP1.

[0151] The track driving signal output from the tracking control circuit28 is supplied to the driving coil 11 in the tracking direction. Thetrack difference signal used in the tracking control circuit 28 issupplied to the linear motor control circuit 8.

[0152] With the above focusing and tracking operations, the sum signalof the output signals from the photodetection cells 24 a, 24 b, 24 c,and 24 d of the photodetector 24, i.e., an output signal from an adder26 e which is obtained by adding the two output signals from the adders26 c and 26 d, reflects changes in reflectance due to the data recordedon the optical disk 1. The output signal from the adder 26 e is suppliedto the data reproducing circuit 16.

[0153] The data reproducing circuit 16 reproduces the data reflected inthe output signal from the adder 26 e and recorded on the optical disk.The reproduced data reproduced by the data reproducing circuit 16 issubjected to error correction in the error correction circuit 32. Theresultant data is output to an optical disk controller 36 through aninterface circuit 35. In addition, the record data output from theoptical disk controller 36 is supplied to the error correction circuit32 through the interface circuit 35 and a bus 29.

[0154] While the objective lens 10 is moved by the tracking controlcircuit 28, the optical head 5 is moved by the linear motor controlcircuit 8 such that the objective lens 10 is located near the centerposition of the optical head 5.

[0155] A D/A converter 31 is used to exchange data between the focusingcontrol circuit 27, the tracking control circuit 28, the linear motorcontrol circuit 8, and the CPU 30.

[0156] The motor control circuit 4, the linear motor control circuit 8,the laser driving circuit 15, the PLL circuit 18, the data reproducingcircuit 16, the focusing control circuit 27, the tracking controlcircuit 28, the error correction circuit 32, and the like are controlledby the CPU 30 through the bus 29. The CPU 30 performs predeterminedoperations in accordance with the programs recorded on the lead-in area2.

[0157] The data reproducing circuit 16 will be described in detail nextwith reference to FIG. 17.

[0158] As shown in FIG. 17, the data reproducing circuit 16 isconstituted by a binarization circuit 61, a shift register 62, ademodulation circuit 63, an address mark detection circuit 64 as anaddress mark detection means, a word boundary counter 65, an IED checkcircuit 66, an address data reproducing circuit 67, and a headerdetection signal generating circuit 68.

[0159] The binarization circuit 61 binarizes an addition signal suppliedfrom the adder 26 e. The binary signal from the binarization circuit 61is supplied to the PLL circuit 18 to be converted into a data sequence(channel data) synchronized with a reproduction clock signal (channelclock).

[0160] Channel clock and channel data as output signals from the PLLcircuit 18 are supplied to the 16-bit shift register 62. This channelclock is also supplied to the demodulation circuit 63, the address markdetection circuit ⁶⁴, and the word boundary counter 65.

[0161] The shift register 62 converts the channel data supplied from thePLL circuit 18 into 16-bit parallel data, and outputs the parallel data.The 16-bit channel data output from the shift register 62 is supplied tothe demodulation circuit 63 and the address mark detection circuit 64.

[0162] The demodulation circuit 63 includes a demodulation ROM and aparallel/serial conversion section (neither of which are shown). Dataabout 8-16 modulation is stored in the demodulation ROM. The 16-bitchannel data supplied from the shift register 62 is demodulated into8-bit data on the basis of the data about 8-16 modulation stored in thedemodulation ROM. In the demodulation mode, the word boundary signalsupplied from the word boundary counter 65 is used. In addition, thedemodulation circuit 63 frequency-divides the channel clock suppliedfrom the PLL circuit 18 to generate a data clock. The parallel/serialconversion section converts the demodulated 8-bit data into serial datain accordance with the data clock.

[0163] The serial data supplied from the demodulation circuit 63 isoutput to the IED check circuit 66 and the address data reproducingcircuit 67. The data clock generated by the demodulation circuit 63 isoutput to the IED check circuit 66, the address data reproducing circuit67, and the header detection signal generating circuit 68.

[0164] The address mark detection circuit 64 includes a ROM and acomparator (neither of which are shown). The address mark (channel bitdata) shown in FIG. 5 is stored in the ROM. The comparator compares thechannel bit data supplied from the shift register 62 with the addressmark stored in the ROM. If the comparison result obtained by thecomparator indicates that the channel bit data supplied from the shiftregister 62 coincides with the address mark stored in the ROM, theaddress mark detection circuit 64 outputs an address mark detectionsignal. The address mark detection signal output from the address markdetection circuit 64 is supplied to the word boundary counter 65, theIED check circuit 66, the address data reproducing circuit 67, and theheader detection signal generating circuit 68.

[0165] As described above, the address mark stored in the ROM of theaddress mark detection circuit 64 includes a special pattern which doesnot appear in any patterns reproduced from other fields. The use of theaddress mark shown in FIG. 5 therefore prevents a detection error of anaddress mark.

[0166] The word boundary counter 65 starts counting in response to theaddress mark detection signal supplied from the address mark detectioncircuit 64 as a trigger, and outputs a word boundary signal in units offixed-length block codes (16 channel bits). The word boundary signalfrom the word boundary counter 65 is output to the demodulation circuit63.

[0167] The IED check circuit 66 receives the address mark detectionsignal supplied from the address mark detection circuit 64. At thistime, the IED check circuit 66 receives the PID data recorded in thePIDn field (n: 1 to 4) and the error detection code recorded in the IEDnfield (n: 1 to 4) on the basis of the data clock supplied from thedemodulation circuit. The IED check circuit 66 then checks the PID dataon the basis of the error detection code. The check result obtained bythe IED check circuit 66 is output to the header detection signalgenerating circuit 68.

[0168] The address data reproducing circuit 67 reproduces the addressdata recorded in the PID field on the basis the identification resultsupplied from the comparator 67 a, the address mark detection signalsupplied from the address mark detection circuit 64, and the data clocksupplied from the demodulation circuit 63. The header detection signaloutput from the header detection signal generating circuit 68 issupplied to the PLL circuit 18 and the CPU 30.

[0169] If, for example, a check result indicating the absence of anerror and an identification result indicating PID1 are supplied to theheader detection signal generating circuit 68, the header detectionsignal generating circuit 68 generates a header detection signal 94bytes after the address mark detection signal is supplied.

[0170] If a check resulting indicating the absence of an error and anidentification result indicating PID2 are supplied to the headerdetection signal generating circuit 68, the header detection signalgenerating circuit 68 generates a header detection signal 76 bytes after the address mark detection signal is supplied.

[0171] If a check resulting indicating the absence of an error and anidentification result indicating PID3 are supplied to the headerdetection signal generating circuit 68, the header detection signalgenerating circuit 68 generates a header detection signal 30 bytes afterthe address mark detection signal is supplied.

[0172] If a check resulting indicating the absence of an error and anidentification result indicating PID4 are supplied to the headerdetection signal generating circuit 68, the header detection signalgenerating circuit 68 generates a header detection signal 12 bytes afterthe address mark detection signal is supplied.

[0173] To recapitulate, according to the present invention, thefollowing information recording medium, cutting apparatus, andinformation reproducing apparatus can be provided:

[0174] (1) an information recording medium on which--an address markwhich can be normally detected even if a defective pit is included in aVFO field is recorded;

[0175] (2) a cutting apparatus for recording by exposure an address markwhich can be normally detected even if a defective pit is included in aVFO field on a master for an information recording medium; and

[0176] (3) an information reproducing apparatus for reproducing addressdata in accordance with an address mark which can be normally detectedeven if a defective pit is included in a VFO field.

[0177] Additional advantages and modifications will readily occur tothose skilled in the art. Therefore, the invention in its broaderaspects is not limited to the specific details and representativeembodiments shown and described herein. Accordingly, variousmodifications may be made without departing from the spirit or scope ofthe general inventive concept as defined by the appended claims andtheir equivalents.

1. An information recording medium including a plurality of sectorfields and having various pieces of information recorded in said sectorfields, wherein said sector field comprises: a header field in which anaddress mark including a violation pattern exceeding a run lengthlimitation in a predetermined range and address data complying with therun length limitation in the predetermined range, a recording positionof which is indicated by the address mark, are recorded; and a recordingfield on/from which data is recorded/reproduced on the basis of the datarecorded in said header field.
 2. A medium according to claim 1 ,wherein said header field includes: a first field in which acontinuously repeated pattern complying with the run length limitationin the predetermined range is recorded; a second field in which theaddress mark including the violation pattern different from a reproducedpattern obtained by reproducing the repeated pattern when a defectivepit which cannot be recognized as a pit is includes in pits representingthe repeated pattern is recorded; and a third field in which the addressdata is recorded.
 3. A medium according to claim 1 , wherein said headerfield includes: a first field in which a continuously repeated patterncomplying with a run length limitation in a specific range from a valuelarger than a lower limit value to an upper limit value in thepredetermined range is recorded; a second field in which the addressmark including the violation pattern different from a reproduced patternobtained by reproducing the repeated pattern when a defective pit whichcannot be recognized as a pit is include in pits representing therepeated pattern is recorded; and a third field in which the addressdata is recorded.
 4. A medium according to claim 1 , wherein said headerfield includes: a first field in which a continuously repeated patterncomplying with a run length limitation in a specific range from a valuelarger than a lower limit value to an upper limit value in thepredetermined range is recorded; a second field in which the addressmark including the violation pattern different from a reproduced patternobtained by reproducing the repeated pattern when a defective pit whichcannot be recognized as a pit is included in its representing therepeated pattern is recorded; and a third field in which the addressdata is recorded, and said recording field includes a fourth field inwhich a code complying with the run length limitation in thepredetermined range is recorded.
 5. A medium according to claim 1 ,wherein said header field includes: a first field in which acontinuously repeated pattern satisfying a run length of 3 is recorded;a second field in which the address mark including the violation patterndifferent from a reproduced pattern obtained by reproducing the repeatedpattern when a defective pit which cannot be recognized as a pit isincluded in pits representing the repeated pattern is recorded, theviolation pattern exceeding a run length limitation corresponding to runlengths of 2 to 10; and a third field in which the address data isrecorded.
 6. A medium according to claim 1 , wherein said header fieldincludes: a first in which a continuously repeated pattern satisfying arun length of 3 is recorded; a second field in which the address markincluding the violation pattern different from a reproduced patternobtained by reproducing the repeated pattern when a defective pit whichcannot be recognized as a pit is included in pits representing therepeated pattern is recorded, the violation pattern exceeding a runlength limitation corresponding to run lengths of 2 to 10; and a thirdfield in which the address data is recorded, and said recording fieldincludes a fourth field in which a code complying with a run lengthlimitation corresponding to run lengths of 2 to 10 is recorded.
 7. Amedium according to claim 1 , wherein said header field includes: afirst field in which a continuously repeated pattern satisfying a runlength m is recorded; a second field in which the address mark includingthe violation pattern satisfying a run length n (n>m, n≠rm+(r−1), r:natural number) is recorded; and a third field in which the address datais recorded.
 8. A medium according to claim 1 , wherein said headerfield includes: a first field in which a continuously repeated patternsatisfying a run length m is recorded; a second field in which theaddress mark including the violation pattern satisfying a run length n(n>m, n≠rm+(r−1), r: natural number) is recorded; and a third field inwhich the address data is recorded, and said recording field includes afourth field in which a code complying with the run length limitation inthe predetermined range is recorded.
 9. A medium according to claim 1 ,wherein said header field includes: a first field in which acontinuously repeated pattern satisfying a run length of 3 is recorded;a second field in which the address mark including the violation patternsatisfying a run length n (n>3, n≠3r+(r−1), r: natural number) isrecorded; and a third field in which the address data is recorded.
 10. Amedium according to claim 1 , wherein said header field includes: afirst field in which a continuously repeated pattern satisfying a runlength of 3 is recorded; a second field in which the address markincluding the violation pattern satisfying a run length of 13 isrecorded; and a third field in which the address data is recorded.
 11. Amedium according to claim 1 , wherein said header field includes: afirst field in which a continuously repeated pattern satisfying a runlength of 3 is recorded; a second field in which the address markincluding the violation pattern satisfying a run length of 13 isrecorded; and a third field in which the address data is recorded, andsaid recording field includes a fourth field in which a code complyingwith a run length limitation corresponding to run lengths of 2 to 10 isrecorded.
 12. A medium according to claim 1 , wherein said header fieldincludes: a first field in which a continuously repeated patterncomplying with the run length limitation in the predetermined range isrecorded; a second field in which the address mark including a specialpattern having the repeated pattern adjacent to the violation pattern isrecorded; and a third field in which the address data is recorded.
 13. Amedium according to claim 1 , wherein said header field includes: afirst field in which a continuously repeated pattern satisfying a runlength m is recorded; a second field in which the address mark includinga special pattern having repeated pattern adjacent to the violationpattern satisfying a run length n (n>m, n≠rm+(r−1), r: natural number)is recorded; and a third field in which the address data is recorded.14. A medium according to claim 1 , wherein said header field includes:a first field in which a continuously repeated pattern satisfying a runlength of 3 is recorded; a second field in which the address markincluding a special pattern having the repeated pattern adjacent to theviolation pattern satisfying a run length of 13 is recorded; and a thirdfield in which the address data is recorded.
 15. A medium according toclaim 1 , wherein said header field includes: a first field in which acontinuously repeated pattern complying with the run length limitationin the predetermined range is recorded; a second field in which theaddress mark in which a special pattern including an odd number of 1s aschannel bits repeats itself an even number of times is recorded; a thirdfield in which the address data is recorded.
 16. A medium according toclaim 1 , wherein said header field includes: a first field in which acontinuously repeated pattern complying with the run length limitationin the predetermined range is recorded; a second field in which theaddress mark including the violation pattern different from a reproducedpattern obtained by reproducing the repeated pattern when a defectivepit which cannot be recognized as a pit is included in pits representingthe repeated pattern is recorded, a special pattern including an oddnumber of 1s as channel bits repeating itself an even number of times inthe address mark; and a third field in which the address data isrecorded.
 17. A medium according to claim 1 , wherein said header fieldincludes: a first, field in which a continuously repeated patternsatisfying a run length m is recorded; a second field in which theaddress mark including the violation pattern satisfying a run length n(n>m, n≠rm+(r−1), r: natural number) is recorded, a special patternincluding an odd number of is as channel bits repeating itself an evennumber of times in the address mark; and a third field in which theaddress data is recorded.
 18. A medium according to claim 1 , whereinsaid header field includes: a first field in which a continuouslyrepeated pattern complying with the run length limitation in thepredetermined range is recorded; a second field in which the addressmark including a special pattern having the repeated pattern adjacent tothe violation pattern is recorded, a special pattern including an oddnumber of is as channel bits repeating itself an even number of times inthe address mark; and a third field in which the address data isrecorded.
 19. A medium according to claim 1 , wherein said header fieldincludes: a first field in which a continuously repeated patternsatisfying a run length m is recorded; a second field in which theaddress mark including a special pattern having the repeated patternadjacent to the violation pattern satisfying a run length n (n>m,n≠rm+(r−1), r: natural number) is recorded, a special pattern includingan odd number of 1s as channel bits repeating itself an even number oftimes in the address mark; and a third field in which the address datais recorded.
 20. A medium according to claim 1 , wherein said headerfield includes: a first field in which a continuously repeated patternsatisfying a run length of 3 is recorded; a second field in which theaddress mark including an even number of special patterns constituted by22 channel bits having is as channel bits appearing at a 4th channelbit, an 8th channel bit, and a 22nd channel bit is recorded; and a thirdfield in which the address data is recorded.
 21. A cutting apparatus forrecording header data, by exposure, on a master for an informationrecording medium on which various pieces of information are recorded,comprising recording means for recording by exposure an address markincluding a violation pattern exceeding a run length limitation in apredetermined range and address data complying with the run lengthlimitation in the predetermined range, a recording position of which isindicated by the address mark.
 22. An apparatus according to claim 21 ,wherein said recording means includes: first recording means forrecording a continuously repeated pattern complying with the run lengthlimitation in the predetermined range by exposure; second recordingmeans for recording, by exposure, the address mark including theviolation pattern different from a reproduced pattern obtained byreproducing the repeated pattern when a defective pit which cannot berecognized as a pit is included in pits representing the repeatedpattern; and third recording means for recording the address data byexposure.
 23. An apparatus according to claim 21 , wherein saidrecording means includes: first recording means for recording, byexposure, a continuously repeated pattern complying with a run lengthlimitation in a specific range from a value larger than a lower limitvalue to an upper limit value in the predetermined range; secondrecording means for recording, by exposure, the address mark includingthe violation pattern different from a reproduced pattern obtained byreproducing the repeated pattern when a defective pit which cannot berecognized as a pit is included in pits representing the repeatedpattern; and third recording means for recording the address data isrecorded by exposure.
 24. An apparatus according to claim 21 , whereinsaid recording means includes: first recording means for recording acontinuously repeated pattern satisfying a run length of 3 by exposure;second recording means for recording, by exposure, the address markincluding the violation pattern different from a reproduced patternobtained by reproducing the repeated pattern when a defective pit whichcannot be recognized as a pit is included in pits representing therepeated pattern, the violation pattern exceeding a run lengthlimitation corresponding to run lengths of 2 to 10; and third recordingmeans for recording the address data by exposure.
 25. An apparatusaccording to claim 21 , wherein said recording means includes: firstrecording means for recording a continuously repeated pattern satisfyinga run length m by exposure; second recording means for recording theaddress mark including the violation pattern satisfying a run length n(n>m, n≠rm+(r−1), r: natural number) by exposure; and third recordingmeans for recording the address data by exposure.
 26. An apparatusaccording to claim 21 , wherein said recording means includes: firstrecording means for recording a continuously repeated pattern satisfyinga run length of 3 by exposure; second recording means for recording theaddress mark including the violation pattern satisfying a run length n(n>3, n≠3r+(r−1), r: natural number) by exposure; and third recordingmeans for recording the address data by exposure.
 27. An apparatusaccording to claim 21 , wherein said recording means includes: firstrecording means for recording a continuously repeated pattern satisfyinga run length of 3 by exposure; second recording means for recording theaddress mark including the violation pattern satisfying a run length of13 by exposure; and third recording means for recording the address databy exposure.
 28. An apparatus according to claim 21 , wherein saidrecording means includes: first recording means for recording acontinuously repeated pattern complying with the run length limitationin the predetermined range by exposure; second recording means forrecording the address mark including a special pattern having therepeated pattern adjacent to the violation pattern by exposure; andthird recording means for recording the address data by exposure.
 29. Anapparatus according to claim 21 , wherein said recording means includes:first recording means for recording a continuously repeated patternsatisfying a run length m by exposure; second recording means forrecording, by exposure, the address mark including a special patternhaving the repeated pattern adjacent to the violation pattern satisfyinga run length n (n>m, n≠rm+(r−1), r: natural number); and third recordingmeans for recording the address data by exposure.
 30. An apparatusaccording to claim 21 , wherein said recording means includes: firstrecording means for recording a continuously repeated pattern satisfyinga run length of 3 by exposure; second recording means for recording, byexposure, the address mark including a special pattern having therepeated pattern adjacent to the violation pattern satisfying a runlength of 13; and third recording means for recording the address databy exposure.
 31. An apparatus according to claim 21 , wherein saidrecording means includes: first recording means for recording acontinuously repeated pattern satisfying the run length in thepredetermined range by exposure; second recording means for recording,by exposure, the address mark in which a special pattern including anodd number of 1s as channel bits repeats itself an even number of times;third recording means for recording the address data by exposure.
 32. Anapparatus according to claim 21 , wherein said recording means includes:first recording means for recording a continuously repeated patterncomplying with the run length limitation in the predetermined range byexposure; second recording means for recording, by exposure, the addressmark including the violation pattern different from a reproduced patternobtained by reproducing the repeated pattern when a defective pit whichcannot be recognized as a pit is included in pits representing therepeated pattern, a special pattern including an odd number of is aschannel bits repeating itself an even number of times in the addressmark; and third recording means for recording the address data byexposure.
 33. An apparatus according to claim 21 , wherein saidrecording means includes: first recording means for recording acontinuously repeated pattern satisfying a run length m by exposure;second recording means for recording, by exposure, the address markincluding the violation pattern satisfying a run length n (n>m,n≠rm+(r−1), r: natural number), a special pattern including an oddnumber of 1s as channel bits repeating itself an even number of times inthe address mark; and third recording means for recording the addressdata by exposure.
 34. An apparatus according to claim 21 , wherein saidrecording means includes: first recording means for recording acontinuously repeated pattern complying with the run length limitationin the predetermined range by exposure; second recording means forrecording, by exposure, the address mark including a special patternhaving the repeated pattern adjacent to the violation pattern, a specialpattern including an odd number of is as channel bits repeating itselfan even number of times in the address mark; and third recording meansfor recording the address data by exposure.
 35. An apparatus accordingto claim 21 , wherein said recording means includes: first recordingmeans for a continuously repeated pattern satisfying a run length m byexposure; second recording means for recording, by exposure, the addressmark including a special pattern having the repeated pattern adjacent tothe violation pattern satisfying a run length n (n>m, n≠rm+(r−1), r:natural number), a special pattern including an odd number of 1s aschannel bits repeating itself an even number of times in the addressmark; and third recording means for recording the address data byexposure.
 36. An apparatus according to claim 21 , wherein saidrecording means includes: first recording means for recording acontinuously repeated pattern satisfying a run length of 3 by exposure;second recording means for recording, by exposure, the address markincluding an even number of special patterns constituted by 22 channelbits having 1s as channel bits appearing at a 4th channel bit, an 8thchannel bit, and a 22nd channel bit; and third recording means forrecording the address data by exposure.
 37. An information reproducingapparatus for reproducing information recorded on an informationrecording medium on which various pieces of information are recorded,comprising: address mark detection means for detecting an address markfrom a header field in which the address mark including a violationpattern exceeding a run length limitation in a predetermined range andaddress data complying with the run length limitation in thepredetermined range, a recording position of which is indicated by theaddress mark, are recorded; and reproducing means for reproducing theaddress data in accordance with type address mark detected by saidaddress mark detection means.
 38. An apparatus according to claim 37 ,wherein said header field includes: a first yield in which acontinuously repeated pattern complying with the run length limitationin the predetermined range is recorded; a second field in which theaddress mark including the violation pattern different from a reproducedpattern obtained by reproducing the repeated pattern when a defectivepit which cannot be recognized as a pit is included in pits representingthe repeated pattern is recorded; and a third field in which the addressdata is recorded, and said address mark detection means includesdetection means for detecting the address mark from said header fieldincluding said first, second, and third fields.
 39. An apparatusaccording to claim 37 , wherein said header field includes: a firstfield in which a continuously repeated pattern complying with a runlength limitation in a specific range from a value larger than a lowerlimit value to an upper limit value in the predetermined range isrecorded; a second field in which the address mark including theviolation pattern different from a reproduced pattern obtained byreproducing the repeated pattern when a defective pit which cannot berecognized as a pit is included in pits representing the repeatedpattern is recorded; and a third field in which the address data isrecorded, and said address mark detection means includes detection meansfor detecting the address mark from said header field including saidfirst, second, and third fields.
 40. An apparatus according to claim 37, wherein said header field includes: a first field in which acontinuously repeated pattern satisfying a run length of 3 is recorded;a second field in which the address mark including the violation patterndifferent from a reproduced pattern obtained by reproducing the repeatedpattern when a defective pit which cannot be recognized as a pit isincluded in pits representing the repeated pattern is recorded, theviolation pattern exceeding a run length limitation corresponding to runlengths of 2 to 10; and a third field in which the address data isrecorded, and said address mark detection means includes detection meansfor detecting the address mark from said header field including saidfirst, second, and third fields.
 41. An apparatus according to claim 37, wherein said header field includes: a first field in which acontinuously repeated pattern satisfying a run length m is recorded; asecond field in which the address mark including the violation patternsatisfying a run length n (n>m, n≠rm+(r−1), r: natural number) isrecorded; and a third field in which the address data is recorded, andsaid address mark detection means includes detection means for detectingthe address mark from said header field including said first, second,and third fields.
 42. An apparatus according to claim 37 , wherein saidheader field includes: a first field in which a continuously repeatedpattern satisfying a run length of 3 is recorded; a second field inwhich the address mark including the violation pattern satisfying a runlength n (n>3, n≠3r+(r−1), r: natural number) is recorded; and a thirdfield in which the address data is recorded, and said address markdetection means includes detection means for detecting the address markfrom said header field including said first, second, and third fields.43. An apparatus according to claim 37 , wherein said header fieldincludes: a first field in which a continuously repeated patternsatisfying a run length of 3 is recorded; a second field in which theaddress mark including the violation pattern satisfying a run length of13 is recorded, and a third field in which the address data is recorded,and said address mark detection means includes detection means fordetecting the address mark from said header field including said first,second, and third fields.
 44. An apparatus according to claim 37 ,wherein said header field includes: a first field in which acontinuously repeated pattern complying with the run length limitationin the predetermined range is recorded; a second field in which theaddress mark including a special pattern having the repeated patternadjacent to the violation pattern is recorded; and a third field inwhich the address data is recorded, and said address mark detectionmeans includes detection means for detecting the address mark from saidheader field including said first, second, and third fields.
 45. Anapparatus according to claim 37 , wherein said header field includes: afirst field in which a continuously repeated pattern satisfying a runlength m is recorded; a second field in which the address mark includinga special pattern having the repeated pattern adjacent to the violationpattern satisfying a run length n (n>m, n≠rm+(r−1), r: natural number)is recorded; and a third field in which the address data is recorded,and said address mark detection means includes detection means fordetecting the address mark from said header field including said first,second, and third fields.
 46. An apparatus according to claim 37 ,wherein said header field includes: a first field in which acontinuously repeated pattern satisfying a run length of 3 is recorded;a second field in which the address mark including a special patternhaving the repeated pattern adjacent to the violation pattern satisfyinga run length of 13 is recorded; and a third field in which the addressdata is recorded, and said address mark detection means includesdetection means for detecting the address mark from said header fieldincluding said first, second, and third fields.
 47. An apparatusaccording to claim 37 , wherein said header field includes: a firstfield in which a continuously repeated pattern satisfying the run lengthin the predetermined range is recorded; a second field in which theaddress mark in which a special pattern including an odd number of 1s aschannel bits repeats itself an even number of times is recorded; a thirdfield in which the address data is recorded, and said address markdetection means includes detection means for detecting the address markfrom said header field including said first, second, and third fields.48. An apparatus according to claim 37 , wherein said header fieldincludes: a first field in which a continuously repeated patterncomplying with the run length limitation in the predetermined range isrecorded; a second field in which the address mark including theviolation pattern different from a reproduced pattern obtained byreproducing the repeated pattern when a defective pit which cannot berecognized as a pit is included in pits representing the repeatedpattern is recorded, a special pattern including an odd number of is aschannel bits repeating itself an even number of times in the addressmark; and a third field in which the address data is recorded, and saidaddress mark detection means includes detection means for detecting theaddress mark from said header field including said first, second, andthird fields.
 49. An apparatus according to claim 37 , wherein saidheader field includes: a first field in which a continuously repeatedpattern satisfying a run length m is recorded; a second field in whichthe address mark including the violation pattern satisfying a run lengthn (n>m, n≠rm+(r−1), r: natural number) is recorded, a special patternincluding an odd number of is as channel bits repeating itself an evennumber of times in the address mark; and a third field in which theaddress data is recorded, and said address mark detection means includesdetection means for detecting the address mark from said header fieldincluding said first, second, and third fields.
 50. An apparatusaccording to claim 37 , wherein said header field includes: a firstfield in which a continuously repeated pattern complying with the runlength limitation in the predetermined range is recorded; a second fieldin which the address mark including a special pattern having therepeated pattern adjacent to the violation pattern is recorded, aspecial pattern including an odd number of is as channel bits repeatingitself an even number of times in the address mark; and a third field inwhich the address data is recorded, and said address mark detectionmeans includes detection means for detecting the address mark from saidheader field including said first, second, and third fields.
 51. Anapparatus according to claim 37 , wherein said header field includes: afirst field in which a continuously repeated pattern satisfying a runlength m is recorded; a second field in which the address mark includinga special pattern having the repeated pattern adjacent to the violationpattern satisfying a run length n (n>m, n≠rm+(r−1), r: natural number)is recorded, a special pattern including an odd number of is as channelbits repeating itself an even number of times in the address mark; and athird field in which the address data is recorded, and said address markdetection means includes detection means for detecting the address markfrom said header field including said first, second, and third fields.52. An apparatus according to claim 37 , wherein said header fieldincludes: a first field in which a continuously repeated patternsatisfying a run length of 3 is recorded; a second field in which theaddress mark including an even number of special patterns constituted by22 channel bits having is as channel bits appearing at a 4th channelbit, an 8th channel bit, and a 22nd channel bit is recorded; and a thirdfield in which the address data is recorded, and said address markdetection means includes detection means for detecting the address markfrom said header field including said first, second, and third fields.